Vasculitis rash pain relief advice

Hi anyone with vasculitis rash , how long did it take for rash to away and just not hurt or be itchy been taking prednisone this week but the rash is still bad the doctor just increased the dose from 15 to 20 don't know if it's working cause they it might go down but come back in these weeks but it's getting harder to sleep at night cause of itch ir just the feeling of needles being punched to skin